1. Field of the Invention
The invention relates to the field of antenna. More specifically, a multi-band antenna operates at various wireless communication bands.
2. The Related Art
A portable communication device has an antenna that supports wireless communication in multiple bands, such as global system for mobile communications (GSM). Wireless communication bands include global system for mobile communications (GSM) band about 850 mega-hertz (MHz), extended global system for mobile communications (EGSM) band about 900 MHz, digital cellular system (DCS) band about 1800 MHz and personal conferencing specification (PCS) band about 1900 MHz.
Many different types of antennas for the portable communication device are used, including helix, monopole, inverted-F, dipole, patch, loop and retractable antennas. Helix antenna and retractable antenna are typically installed outside the portable communication device. Inverted-F antenna, monopole antenna, patch antenna, loop antenna and dipole antenna are typically embedded inside the portable communication device case or housing.
Generally, embedded antennas are preferred over external antennas for the portable communication device owing to mechanical and ergonomic reasons. Embedded antennas are protected by the portable communication device case or housing and therefore tend to be more durable than external antennas. Therefore, embedded antenna capable of operating at various wireless communication bands such as GSM band, EGSM band, DCS band and PCS band is an essential component for the portable wireless communication device.